Known examples of the types of the forms of agricultural chemicals include: milky white formulations in the form of concentrated oil-in-water emulsions obtained by emulsifying and dispersing a water-insoluble agricultural chemical active ingredient in water in the form of fine particles by adding an emulsifier (emulsion formulations (emulsion, oil in water: EW or concentrated emulsion: CE)); and thermodynamically stable and transparent formulations obtained by mixing mutually incompatible water and oil in the manner of ordinary emulsions, but consisting of dispersed particles that are much smaller (mean particle diameter: 0.1 μm or less) than the particles of ordinary emulsions (microemulsion formulations (microemulsion: ME)).
More specifically, Patent Document 1 discloses a wood preservative having as an active ingredient thereof an anionic surfactant containing a sulfonate or laurylsulfate ester. A preservative containing a sulfosuccinate ester is described as a comparative example of a formulation in Patent Document 1.
Patent Document 2 discloses a wood preservative, ant repellent and anti-mold agent containing as an active ingredient thereof a polyoxyalkylene alkyl ether obtained by adding at least one type of compound selected from the group consisting of ethylene oxide, propylene oxide and butylene oxide to an alkyl alcohol. A preservative containing a sorbitan fatty acid ester-based surfactant and a preservative containing polyoxyethylene styrenated phenyl ether are described as comparative examples of formulations in Patent Document 2.
Patent Document 3 describes a microemulsion preparation containing: a) one or more agricultural chemical active ingredients; b) one or more non-alcoholic organic solvents; c) one or more anionic surfactants; and d) one or more nonionic surfactants.
Patent Document 4 discloses an emulsion containing a surfactant. Examples of preferable surfactants include: f1) alkoxylation product obtained by ethylene oxide alkoxylation or propylene oxide alkoxylation of a condensation product of an aromatic compound containing a phenolic OH group, formaldehyde and an NH functional group; f2) a carbonate, sulfate and phosphate of an alkaline metal or alkaline earth metal; f3) a polymer containing repeating succinyl units; f4) a non-ionically or ionically modified compound selected from the group consisting of alkoxylate, alkylolamide, ester, amine oxide and alkylpolyglycoside; f5) a reaction product of an alkylene oxide and sorbitan ester, an oxyalkylated acetylenediol and acetylene glycol, and an oxyalkylated phenol; f6) ionically or non-ionically modified polymeric surfactants selected from the group consisting of homo- and copolymers, grafts and graft copolymers, and random and linear block copolymers; f7) anionic surfactants such as ether sulfates, ether carboxylates and phosphate esters; f8) anionic surfactants such as sulfosuccinate esters, alkylbenzene sulfonates and salts of polyacrylic acid, polyethylene sulfonic acid, polystyrene sulfonic acid, polymethacrylic acid or polyphosphoric acid; and f9) lignin-based compounds, and particularly lignosulfonates.
Patent Document 5 discloses a microemulsion-formable concentrate of a hydrophobic agricultural chemical containing: (a) at least one type of hydrophobic agricultural chemical, (b) a concentrate of a first solvent selected from alkyl alkanoates, a polyvalent alcohol, a polyvalent alcohol concentration product and a mixture thereof, and (c) at least one type of surfactant. Examples of the surfactant include cationic surfactants such as polyalkoxylated aliphatic amines, nonionic surfactants such as polyalkylene oxide alkyl ethers, and anionic surfactants such as alkylbenzene sulfonates.
However, the emulsion or microemulsion formulations described in these documents may require a large amount of surfactant or emulsifier corresponding to the solubility of the active ingredient. In such cases, a large amount of foam may form during preparation of the formulation and may be difficult to remove from the formulation container. In the case of diluting the formulations, the stability of the emulsion or microemulsion may decrease. In addition, the use of a large amount of surfactant for the purpose of enhancing solubility results in increased costs.